/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.sun.org.apache.xml.internal.security.transforms.implementations;

import java.io.OutputStream;

import javax.xml.transform.TransformerException;

import com.sun.org.apache.xml.internal.security.exceptions.XMLSecurityRuntimeException;
import com.sun.org.apache.xml.internal.security.signature.NodeFilter;
import com.sun.org.apache.xml.internal.security.signature.XMLSignatureInput;
import com.sun.org.apache.xml.internal.security.transforms.Transform;
import com.sun.org.apache.xml.internal.security.transforms.TransformSpi;
import com.sun.org.apache.xml.internal.security.transforms.TransformationException;
import com.sun.org.apache.xml.internal.security.transforms.Transforms;
import com.sun.org.apache.xml.internal.security.utils.Constants;
import com.sun.org.apache.xml.internal.security.utils.XMLUtils;
import com.sun.org.apache.xml.internal.security.utils.XPathAPI;
import com.sun.org.apache.xml.internal.security.utils.XPathFactory;
import org.w3c.dom.DOMException;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

/**
 * Class TransformXPath
 *
 * Implements the <CODE>http://www.w3.org/TR/1999/REC-xpath-19991116</CODE>
 * transform.
 *
 * @author Christian Geuer-Pollmann
 * @see <a href="http://www.w3.org/TR/1999/REC-xpath-19991116">XPath</a>
 */
public class TransformXPath extends TransformSpi {

  /**
   * Field implementedTransformURI
   */
  public static final String implementedTransformURI = Transforms.TRANSFORM_XPATH;

  /**
   * Method engineGetURI
   *
   * @inheritDoc
   */
  protected String engineGetURI() {
    return implementedTransformURI;
  }

  /**
   * Method enginePerformTransform
   *
   * @inheritDoc
   */
  protected XMLSignatureInput enginePerformTransform(
      XMLSignatureInput input, OutputStream os, Transform transformObject
  ) throws TransformationException {
    try {
      /**
       * If the actual input is an octet stream, then the application MUST
       * convert the octet stream to an XPath node-set suitable for use by
       * Canonical XML with Comments. (A subsequent application of the
       * REQUIRED Canonical XML algorithm would strip away these comments.)
       *
       * ...
       *
       * The evaluation of this expression includes all of the document's nodes
       * (including comments) in the node-set representing the octet stream.
       */
      Element xpathElement =
          XMLUtils.selectDsNode(
              transformObject.getElement().getFirstChild(), Constants._TAG_XPATH, 0);

      if (xpathElement == null) {
        Object exArgs[] = {"ds:XPath", "Transform"};

        throw new TransformationException("xml.WrongContent", exArgs);
      }
      Node xpathnode = xpathElement.getChildNodes().item(0);
      String str = XMLUtils.getStrFromNode(xpathnode);
      input.setNeedsToBeExpanded(needsCircumvent(str));
      if (xpathnode == null) {
        throw new DOMException(
            DOMException.HIERARCHY_REQUEST_ERR, "Text must be in ds:Xpath"
        );
      }

      XPathFactory xpathFactory = XPathFactory.newInstance();
      XPathAPI xpathAPIInstance = xpathFactory.newXPathAPI();
      input.addNodeFilter(new XPathNodeFilter(xpathElement, xpathnode, str, xpathAPIInstance));
      input.setNodeSet(true);
      return input;
    } catch (DOMException ex) {
      throw new TransformationException("empty", ex);
    }
  }

  /**
   * @return true if needs to be circumvent for bug.
   */
  private boolean needsCircumvent(String str) {
    return (str.indexOf("namespace") != -1) || (str.indexOf("name()") != -1);
  }

  static class XPathNodeFilter implements NodeFilter {

    XPathAPI xPathAPI;
    Node xpathnode;
    Element xpathElement;
    String str;

    XPathNodeFilter(Element xpathElement, Node xpathnode, String str, XPathAPI xPathAPI) {
      this.xpathnode = xpathnode;
      this.str = str;
      this.xpathElement = xpathElement;
      this.xPathAPI = xPathAPI;
    }

    /**
     * @see com.sun.org.apache.xml.internal.security.signature.NodeFilter#isNodeInclude(org.w3c.dom.Node)
     */
    public int isNodeInclude(Node currentNode) {
      try {
        boolean include = xPathAPI.evaluate(currentNode, xpathnode, str, xpathElement);
        if (include) {
          return 1;
        }
        return 0;
      } catch (TransformerException e) {
        Object[] eArgs = {currentNode};
        throw new XMLSecurityRuntimeException("signature.Transform.node", eArgs, e);
      } catch (Exception e) {
        Object[] eArgs = {currentNode, Short.valueOf(currentNode.getNodeType())};
        throw new XMLSecurityRuntimeException("signature.Transform.nodeAndType", eArgs, e);
      }
    }

    public int isNodeIncludeDO(Node n, int level) {
      return isNodeInclude(n);
    }

  }
}
